Study On The Impact Of Urban Heat Island On The Energy Consumption Of Buildings

This thesis analysed the impact of Tianjin urban heat island on the energyconsumption of buildings.Air temperatures in densely built urban areas are higher than the temperatures ofthe surrounding countryside. This phenomenon, known as "urban heat island (UHI)",is worsening by the increased industrialization and urbanization in recent years. Itaffected dramatically the energy consumption of urban buildings. In this paper, degreedays/ hours and dynamic modeling methods were used to estimate the energy use ofreferenced buildings.Climatic measurements from several urban sites and weather station in Tianjin,China, have been performed from Jul 2003 to Jun 2004. It was found that for the cityof Tianjin, where the peak and the mean heat island intensities were 8.12℃, 1.81℃for summer and 5.50, 1.93 for winter. In the central Tianjin area, the heatingdegree-days were 11.2% lower than the suburban area. At the same time, the coolingdegree-hours presented 63% higher than the weather station.The weather file, which was essential for simulation, was completed based on thetemperature data that was mentioned above. The new-generation simulation softwareEnergyPlus that was developed by US DOE was used to estimate the energyperformance of tow prototype building: office and residence. It was shown that: (1)The energy demand for cooling increased 16.73%/℃for office building and 13.82%/℃for residence in summer. And the COP value of air conditioner was decreasedbecause of higher ambient temperature. (2) The energy demand for heating decreased7.21%/℃for office building and 2.05%/℃for residence in winter. (3) The energyuse for total year increased 3.0kWh/m2 for office building and 0.68kWh/m2 forresidence.Finally, the influence of UHI on building energy consumption was discussedwhen changing the two factors: thermal sensitivity of building envelopes and indoordesign temperature. The result showed that changing the two factors could not onlysave energy consumption but also reduce the impact of UHI on building energydemand.